Hand carts, dollies or hand trucks provide an efficient way for a single individual to move a heavy load by sliding it onto a flat ledge and using leverage to balance the load over a pair of wheels. This enables the load to be rolled, rather than lifted and carried, to a selected location. Hand trucks generally consist of an elongated open framework with wheels at the base and a transverse, flat toe plate. In the upright position, the toe plate rests on the floor and can be slid under the load and used to tip it backward onto the frame. The hand truck is rolled in a tipped position, with the load balanced between the toe plate and the open framework. The design of hand carts have been well-known and used within many different industries for the transportation of many diverse types of items.
While the open framework typically can accommodate loads that exceed the width of the frame side rails, smaller items and items having irregular shapes may slip through the open frame and loads of such items are not stable on the hand truck. Narrow items generally will not sit flat between the frame elements, causing them to tilt between the frame elements and become less stable as other items are stacked on top. Even items of mixed sizes may be difficult to transport. As additional items are stacked on top, the load becomes less stable. When the hand truck is tipped backwardly toward the operator, smaller items may fall through the frame. Items that are dislodged during transport cause a trip hazard and may result in shifting or collapse of the entire load with resulting damage to the freight and/or injury to the hand truck operator. Thus, hand trucks are not well-suited for transport of items of mixed sizes, particularly small or irregularly shaped items. For these reasons, it is not uncommon to observe a hand truck operator using one hand to steer the dolly while using the other hand to steady the load. Workers sometimes operate in pairs to transport an unstable load, so that one person can push and steer the hand truck while the other walks alongside to steady the load as needed. This decreases the efficiency of transportation since more than a single worker is required and the stability of the load overall can lead to items falling off during transportation.
In recent years, convertible hand trucks have been developed which are adjustably positionable between an upright configuration supported on two wheels, and a recumbent, cart-like configuration in which the frame is supported by four wheels. If equipped with a solid load bearing surface, such convertible hand trucks could be used in either their upright or recumbent configuration to carry quantities of smaller items that might otherwise escape through an open frame. Use of a solid bearing surface also allows items to be more evenly distributed over the surface, making the load more stable and easier to transport.
While hand trucks with permanently attached platforms are available, they are heavier than the open frame models, more cumbersome to transport, and substantially more expensive. In order to obtain a detachable hand truck platform, many users have constructed their own platforms or decks which are fastened to the frame by various types of fasteners. Such homemade platforms are generally constructed of plywood and are heavy, ill-fitting, unsightly, cumbersome to install and remove, and are limited to use on the particular hand truck for which they were designed. In addition, when used with convertible hand trucks, they must be removed and reinstalled each time the platform is reconfigured. This decreases the overall effectiveness of the product and limits its general ease of use. Few commercial platform accessories have been developed for use with hand trucks. Although presenting a more polished appearance, these platforms are substantially less economical and are designed for use with particular hand trucks made by the same manufacturer and are not interchangeable for configuration or use on other hand trucks. Because the commercial platforms are designed for a only a single hand truck these accessories are generally not compatible with hand trucks of a different type even obtained from the same manufacturer, or with hand trucks obtained from different manufacturers.
Convertible hand trucks present a particular problem, because a deck structure is generally most needed when the truck frame is in a lowered or recumbent position, with all four wheels engaging the ground to form a cart-like structure. However, a deck may interfere with the ability to position an upright hand truck to its recumbent position, or to reposition the hand truck to its upright position. This may be exacerbated by a deck fastening system, which is generally tailored to a particular hand cart. The inconvenience associated with removal and reinstallation of the deck each time the hand truck must be reconfigured effectively limits the utility and versatility of the hand truck.
Thus, there is a need for a universal platform or deck that can be used on hand trucks available from a wide variety of manufacturers, that can be easily installed and removed by a user without the need for tools and fasteners, and that can be installed on convertible hand trucks and remain in place when such hand trucks are adjustably positioned between an upright and a recumbent position to form either a two-wheeled device or a four-wheeled cart.